PECTORAL REGION
AND AXILLA
• By:
• PROF. Saeed Abuel Makarem
• DR.SANAA AL-SHAARAWY
OBJECTIVES
• At the end of the lecture the students should
be able to :
• Identify and describe the muscles of the pectoral
region.
 Pectoralis major.
 Pectoralis minor.
 Subclavius.
 Serratus anterior.
• Describe and demonstrate the boundaries and contents
of the axilla.
Pectoralis Major
• Origin :
• Clavicular head:
• From medial ½ of the front of the
clavicle.
• Sternocostal head: From ,
• Sternum.
• Upper 6 costal cartilages.
• Aponeurosis of external oblique.
• Insertion :
• Lateral lip of bicipital groove.
• Nerve supply :
• Medial & lateral pectoral
nerves.
• Action :
• Adduction and medial rotation
of the arm.
• Clavicular head helps in flexion
of arm (shoulder).
Pectoralis Minor
• Origin:
• from 3rd , 4th , and 5th
ribs close to their costal
cartilages.
• Insertion:
• coracoid process.
• Nerve supply:
• medial pectoral nerve.
• Action:
• Depression of shoulder.
• Draw the ribs upward
and outwards during
deep inspiration
Subclavius
• Origin:
• From 1st rib at the
junction with its costal
cartilage.
• Insertion:
• Subclavian groove at
the inferior surface of
middle 1/3 of clavicle.
• Nerve supply:
• Nerve to subclavius
from upper trunk of
brachial plexus.
• Action:
• Steadies the clavicle
during movement of
the shoulder joint.
Clavipectoral Fascia
• It is a thickened
membrane of deep
fascia between the
subclavius and
pectoralis minor.
• It is pierced by :
 Lateral pectoral nerve.
 Thoraco-acromial
artery
 Cephalic vein.
 Few lymph vessels.
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Origin:
Upper eight ribs.
Insertion:
Ventral aspect of
medial border and
inferior angle of
scapula.
Nerve supply:
Long thoracic nerve.
Action:
Draws the scapula
forward (protraction,
in boxing).
Rotates scapula
outwards in raising
the arm above 90
degree.
Serratus anterior
The Axilla
• A pyramid-shaped
space between the
upper part of the arm
and the side of the
chest through which
major neurovascular
structures(Axillary
vessels & nerves)
pass between neck
& thorax and upper
extremity.
• Axilla has an apex, a
base and four walls
Boundaries of the
Axilla
 Apex:
 Is directed upwards
into the root of the
neck.
 is bounded, by 3
bones:
• Clavicle anteriorly.
• Upper border of
the scapula
posteriorly.
• Outer border of the
first rib medially.
• It is called cervicoaxillary canal.
 Base:
 Formed by skin stretching
between the anterior and
posterior walls.
 is bounded:
• In front by the anterior
axillary fold (formed by
the lower border of the
Pectoralis major
muscle).
• behind by the
posterior axillary fold
(formed by the tendon
of latissimus dorsi and
the teres major
muscle).
• medially by the ribs
and the chest wall.
 Anterior wall:
 Is formed by
• Pectoralis major
• Pectoralis minor
• Subclavius
• Clavipectoral
fascia:
Clavipectoral fascia
Pectoralis
minor
Pectoralis
major
• Posterior wall:
• Is formed by:
• Subscapularis
• Latissimus
dorsi
• Teres major
muscles
 The medial wall:
 Is formed by:
• Serratus anterior
• Upper 4-5 ribs &
Intercostal
muscles .
 The lateral wall:
 Is formed by:
• Coracobrachialis
• Biceps brachii
• Intertubercular
groove of the
humerus.
Contents of The
Axilla
• Cords and
braches of
brachial plexus.
• Axillary artery and
its branches.
• Axillary vein and its
tributaries.
• Axillary lymph
nodes.
• Axillary fat.
• Loose connective
tissue.
Axillary a. & v.
Brachial
plexus
The neurovascular bundle is enclosed in
connective tissue sheath, called ‘axillary sheath’
What is a Brachial Plexus ?
Brachial Plexus is a network of nerves that present at
the root of the neck to enter the upper limb
Location & Formation
Brachial Plexus is present in the posterior triangle
of the neck & axilla
It is formed by the union of the anterior Rami of the
C 5th, 6th, 7th & 8th and the 1st thoracic spinal nerve.
The roots of C5 & C6 unite to form Upper trunk
The root of C7 continues as the Middle trunk
The roots of C8 & T1 unite to form Lower trunk
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The Plexus can be divided into 5 stages:
Roots: in the posterior∆
Trunks: in the posterior∆
Divisions: behind the clavicle
Cords: in the axilla
Branches: in the axilla
• The first 2 stages lie in the posterior triangle, while the last 2 sages lie in the axilla. 16
 The anterior divisions of the upper and middle trunks unite to
form the Lateral cord.
 The anterior division of the lower trunk continues as the Medial
cord.
 All the posterior divisions of three trunks join to form the
Posterior cord.
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Lateral cord
Medial cord
Posterior cord
Lateral pectoral nerve.
Medial pectoral nerve.
Axillary nerve.
Musculocutaneous nerve.
Ulnar nerve.
Radial nerve.
Median nerve (lateral
root).
Median nerve (medial
root).
Upper & lower
subscapular nerves.
Medial cutaneous nerve of Thoracodorsal N.
arm & forearm.
B
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C
H
E
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SUMMARY
Muscles connecting the upper limb with anterior
and lateral thoracic wall are the muscles of pectoral
region, these are :
Pectoralis major.
Pectoralis minor.
Subclavius.
Serratus anterior.
The axilla is a pyramidal space situated between the upper part
of arm and the side of the chest, it has 4 walls (anterior, posterior,
medial and lateral), base, and apex.
The axilla is very important space because it contains :
Axillary vessels.
Cords of brachial plexus and their branches.
Axillary lymph nodes.
Boundaries of Axilla
superiorly: by the outer border of first
rib, superior border of scapula, and
posterior border of clavicle.
medially: serratus anterior and
by the ribcage
anteriorly: by the pectoralis major,
minor, and subclavius (see also anterior
axillary fold).
posteriorly: by the subscapularis
above, and teres major and latissimus
dorsi below (see also posterior axillary
fold)
floor/base: by the skin (visible surface
of armpit)
laterally: by the intertubercular sulcus
(coracobrachialis and the short head of
the biceps brachii are in the axilla.)
THANK YOU